Abstract: We present three cases of isolated adrenocorticotropin
(ACTH) deficiency accompanied by derangement of the thyroid-stimulating
hormone
(TSH)-thyroidal axis. Thyroid hormone and TSH levels were evaluated before
and after cortisol replacement. Although markedly elevated levels of
TSH were noted in one case, this patient also showed typical features
of Hashimoto's thyroiditis. In the other two cases, basal TSH levels
were increased, and replacement of cortisol reversed the values. We have
previously reported that interference of thyroid hormone synthesis and/or
secretion by glucocorticoid deficiency is a major cause of TSH-thyroidal
axis derangement. However, it has been shown that a considerable number
of reported cases exhibit severe hypothyroidism due to Hashimoto's thyroiditis,
as was shown in case 2. It has been recognized that, whether the origin
is the pituitary or the adrenal gland, polyglandular failure is a complex
of autoimmune endocrinopathy. Alternatively, it is assumed that depletion
of the physiological concentration of cortisol may worsen hypothyroidism
due to Hashimoto's thyroiditis, possibly through modification of T cell
function. Since transient abnormalities of the TSH-thyroidal axis and
growth hormone could occur in glucocorticoid-deficient patients along
with derangement of other pituitary hormones, hormonal evaluation should
be carried out after a sufficiently long interval following cortisol
replacement.Keywords: adrenocorticotropic hormone deficiency, hypothyroidism,
hypocortisolism, Hashimoto's thyroiditisJ Saitama Med School 2004;31:115-120
(Received February 23, 2004)